
Class QC S'ZJ 
Book_ 



as 

JsA-JLL 



Copyrights 



COPYRIGHT DEPOSIT. 



ACTIONS 

of 

ELECTRICITY 




/a. 
By LAND IS 

1916 



U. B. PUBLISHING HOUSE 
Dayton, Ohio 



.b3 



Copyrighted by 

Electrical Education Association 1916 

Arcanum, Ohio, U. S. A. 




APFT 10 1916 

2&A427776 

4^0 / , 



PREFACE 

Electricity at the present age is the most used and 
most convenient form of energy or power in the world. 
Its promises for increased use in the future for power 
and other utilities are beyond conception ; yet, with the 
foregoing facts, it is also true that a smaller per cent, 
of people really understand the electric current's ac- 
tions than almost any other science. Referring to the 
above conditions, it is intended by the writer that the 
primary principles of the most commonly used elec- 
trical appliances can be obtained by following the work 
of this book, which is not so lengthy as to become 
tiresome. Again, it must be remembered that the 
entire knowledge of electricity is beyond the space of 
any single book; and if it is desired to become fully 
familiar with all the subjects, terms, measurements, 
etc., numerous volumes of a standard electrical work 
or a special electrical course should be secured. 

J. A. Landis, 
Author. 



ELECTRICITY 

In collecting and explaining a few of the most 
important principles and actions of electricity used so 
extensively in the world, it will be the intention of the 
writer to explain to the reader, by the aid of the small 
motor, in a practical way, some of the causes, actions, 
and results of the electric current used to-day to run 
the world's factories, pull its trains, light darkness, 
start its automobiles, in fact, used by nearly every 
person in some manner. 

It is intended that the small motor be used in con- 
nection with the study of these instructions, thereby 
gaining the practical knowledge of what causes elec- 
tricity and how it is harnessed and used for results 
after it is caused to be. It is therefore necessary for 
the reader to notice the connections, wirings, etc., 
which can easily be removed or traced to show their 
positions or conditions relative to each other within 
the electric machine. 

In order to gain knowledge of electricity in an easy 
way and remember it, the writer knows by experience 
that it is necessary for practice and theory to go hand 
in hand, as a successful learning of our subject cannot 
be obtained by either one method without the other ; 
and it is for this reason that the small motor accom- 
panies this book; therefore, as each subject is handled, 
the reader is asked to study the make-up, shape, con- 
dition, and action of the machine to which it applies, 
so it will be fixed in his mind what each part is 
expected to do and does do. 

In plunging into our subject, first we will learn that 
electricity does not occupy any space, has no weight, 
will exist in a solid matter, in a perfect vacuum, in 
air, in a liquid, or in the ground ; drawing a conclusion 
from the above to fix a definition for it, we can only 
say electricity is an existing force or an existing energy 
in its own peculiar state of being. 

5 



Actions of Electricity. 

We will next learn that there are two principal 
kinds of electricity with which the world to-day has 
most to do; namely, static and dynamic. 

A static charge tends to prevent the change of 
motion or compel objects to come to a rest; from this, 
we know it is produced by friction in some various 
ways and under certain conditions. Friction between 
rain drops and air currents in the sky often produces 
a static charge of great enough volume that it will 
discharge its energy by flashing to the earth, or another 
position in the sky, and this discharge is known as a 
stroke of lightning. 

A small amount of static electricity can be produced 
and its energy noticed to expend by briskly rubbing 
the fur of a fur-bearing animal, and if the finger is 
held close to a rapidly moving belt. 

With the invention of the X-ray machine, the static 
charge was universally used. It was produced by re- 
volving flat disks, usually about four feet in diameter, 
in opposite directions ; the friction between the rapidly 
moving disks generated a heavy charge of static elec- 
tricity which was led to a special glass tube where it 
would expend its energy by flashing through space 
from one end of the wire to the other, possibly about 
four inches apart. This constant flash will produce 
rays of light so strong that they will penetrate a solid 
mass. Later inventions have proven the dynamic elec- 
tricity for the X-ray more convenient and with as 
good results. 

A dynamic charge, nearly the opposite to a static 
charge, tends to set objects in motion or causes them 
to move relatively from each other. In studying dy- 
namic electricity in the future, we will call it current, 
as it practically is known by those who handle it. 

As the knowledge of our subject rests largely upon 
two properties of the electric current, the reader is 

6 



Actions of Electricity. 

asked to strictly familiarize himself with electric 
measurements and magnetism as herein given, for upon 
these two hinge the conditions and problems of all 
electric work and knowledge. 

The electric current is measured by amperes and 
volts, and its flow depends upon ohms. 

Amperes applies to a given amount or quantity of 
current flowing at some certain moment. 

Volts denotes the pressure or the actual force which 
is pushing a certain current through a conductor. 

Ohms is that property of a conductor which tends to 
stop the flow of an electric current. An ohm is the 
unit of measure for current resistance. 





Figure 


1. 


Conductors : 






Xon-Conductors 


Gold 






Crockery 


Silver 






Glass 


Copper 






Wood fibre 


Iron 






Slate 


Damp ground 






Dry wood 




Tabic 


No. 2 


Standard Gau 


ge B. 


& 


S. Copper Wire 


Number 






Ohms per foot 









.000102 


4 






.00026 


8 






.00065 


12 






.00165 


16 






.0048 


18 






.0065 


20 






.0106 


22 






.0168 


24 






.0267 


26 






.0425 


30 






.1074 



Actions of Electricity. 




Fig. 1. 

ftROWN & SHARPE WIRE GUAGR 'B. & S. W. G>) 



To get the idea of the amount of each term and to 
show their relations to each other, let us remember 
that one ampere is the quantity of current that, at a 
pressure of one volt, will flow through a conductor 
having a resistance of one ohm ; hence the measuring 
term's relation of a current actually flowing is as fol- 
lows : 

Ohms = voltage divided by amperes. 

Voltage = ohms times current. 

Amperes = voltage divided by ohms. 

That we may practically know the amount and value 
of each term by our first experiment, we will refer to 
the "resistance of wire" table. For instance, copper 
wire No. 24 has a resistance of .0267 ohms per foot ; 
forty feet times .0267 will have about one ohm resist- 
ance. If we connect both ends of this wire to a common 

8 



Actions of Electricity. 

dry-cell battery whose voltage is, usually, one volt, a 
current of one volt divided by one ohm, one ampere (the 
exact amount of current flowing in the wire). An 
idea of the strength of one ampere in this case can 
be obtained by opening the circuit and closing it with 
the tongue; the sensation to the tongue is caused by 
the flow of one ampere at a pressure of one volt. 

Again, if ten feet of No. 24 copper wire were used, 
we would have ten times .0267 ohms, or .267 ohms; 
one volt (the battery voltage) divided by .267 ohms 
equals about four amperes, which is, of course, four 
times the volume of the first experiment, and might 
be enough to burn the tongue. 

The zvatt is another term of current volume, and is 
obtained by the product of volts times amperes. Watts 
are generally used when speaking of the capacity of a 
small electric utility; for instance, a forty-watt house 
lamp, when on a 110-volt circuit, will consume forty 
watts divided by 110 volts, or nearly .3 of one ampere. 

Volts times amperes = watts. 

Watts divided by 1,000 = kilowatts. 

Watts divided by 746 = horsepower. 

Volts times amperes times hours = watt hours. 

Watt hours divided by 1,000= kilowatt hours. 

If an electric generator has a capacity of generating 
400 amperes at 110 volts, it is spoken of in practice as 
400 amperes times 110 volts divided by 1,000 watts, 
which will be about 44 kilowatts capacity. 

If it is desired to know how large an engine and 
boiler are required to drive this machine, 400 amperes 
times 110 volts divided by 746 watts will be about sixty 
horsepower. 

Again, if a sixty-watt house lamp burns three hours 
an evening for thirty evenings, it will consume sixty 
watts times three hours times thirty evenings — about 
5,400 watt hours, which divided by 1,000 will be 5.4 

9 



Actions of Electricity. 

kilowatt hours; this times, usually, ten cents per kilo- 
watt hours, equals fifty-four cents, cost of light for 
one month. 

If a power motor has an average load of twenty 
amperes at 220 volts eight hours a day, tw r enty-six 
days in a month, at five cents per kilowatt hour, the 
cost of the current will be twenty amperes times 220 
volts divided by 1,000 multiplied by eight hours times 
twenty-six days, which will be $45.76, cost for the 
month for power. 

The reader is asked to solve various problems made 
by himself with the principles of the foregoing state- 
ments, that he may become more familiar with the 
values and how to find the results of the electric 
measuring terms. 

Resistance within a conductor is, in some cases, a 
necessity to properly handle electricity for results. 

Current flowing against a resistance produces heat 
which is in proportion to the quantity of current flow- 
ing, and is not noticeable until nearly the carrying 
capacity of the conductor is reached, after which, if 
the amperes are allowed to increase, the heat within 
the conductor will increase in proportion until the 
melting point is reached. 

This condition is made use of in the ordinary elec- 
tric glass house lamp, where a small, long conductor 
(placed in a vacuum to prevent oxygen in air from 
burning it) with a high resistance and high melting 
point, is connected into a circuit, the flow of current 
through it causing its temperature to rise to a glowing 
red or white heat. 

Let us remember that if this current's voltage were 
raised, this would force more current through the 
already heated conductor and heat it to a hotter degree 
and probably melt it. . 

10 



Actions of Electricity. 



This condition is also practically true in electric 
heating and cooking, where usually iron wire in the 
form of a coil long enough whose own resistance at a 
certain voltage will allow only current enough to pass 
through it to heat it to almost a red heat, is used. 

Voltmeters, ammeters, and wattmeters properly con- 
nected into a circuit, will show the current's actual 
strength or volume. 

MAGNETISM 

Magnetism is a volume of lines of force which flow 
parallel in a continuous circuit; it was first discovered 
in a metal mined in Asia. 

A magnet is a magnetic conductor usually consist- 
ing of iron or steel, charged with a volume of lines of 
magnetic force which in their circuit leave the magnet 
and return to it again, thereby causing the magnet to 
have what is known as a north pole ( X), or that part 




/7 

/ i i 
4 l l 

>' i \ 
i \ 

\ 



>»^ 


Ftg. 2, 


.<___ 


11 




/ 



Actions of Electricity. 

where the lines of force leave it, and a south pole (S) 
where they enter again. 

Magnets are divided into two classes, permanent and 
artificial. Permanent magnets' material is usually steel, 
and when this material is placed in the path of a dense 
magnetic field or flux, it tends to charge and will per- 
manently retain a quantity of lines of force within 
itself. Nearly all magnetic conductors hold a small 
amount of magnetism when once charged, called resid- 
ual magnetism, but in practice, unless they retain a 
large volume of the lines of force, they are not called 
permanent. 

By noting the direction of flow of the lines of force 
of a magnetic circuit in the diagram, it will be seen 
that lines of force flowing in opposite directions can- 
not occupy the same space at the same time ; hence like 
polarity repels and poles of opposite polarity attract 
each other. The earth is a huge magnet ; its polarity 
is nearly its geographical polarity ; the lines of force 
flow parallel from the north pole, on the surface of 
the earth, and enter it at the south pole, through the 
earth, and out near the north pole, making a contin- 
uous circuit. 

This condition is practically used with the compass, 
which is a magnetically charged magnet in the form 
of a needle suspended to permit it to revolve freely. As 
the earth lines of force in the vicinity of the compass 
will tend to flow through the needle, its resistance being 
lower than the air will cause the lines of force within 
the compass magnet and the lines of force of the earth 
magnet to repel each other until they can flow within 
the needle in the same direction ; hence, the south pole 
of the compass magnet will swing on its axis to a point 
toward a northern direction. It must be remembered 
that, should the compass needle be in the vicinity of 
3 magnet whose lines of force are more dense than the 

12 



Actions of Electricity. 



earth circuit, the compass needle will parallel itself 
with the magnetic flux most dense, because it is the 
stronger. 

Artificial magnets are caused only by the flow of 
electricity. If a current is forced through a conductor, 
there will surround the conductor in a true circle a 




Fig. 3. 
magnetic flux or lines of force; if the current in the 
wire is flowing from the observer, the lines of force 
will flow around the conductor in the same direction 
as the hands of a watch turn when observing it. 

Again, if a number of conductors are in parallel and 
the current is sent in the same direction through them, 
the lines of force that would be circular to each con- 
ductor will surround the entire number of conductors 
in its circuit; in other words, a number of conductors 
with a current passing through them in parallel, will 




Fig. 4. 




<::>«< 



have only one magnetic circuit, which is, of course, as 
many times stronger than one of these conductors as 
there are conductors. 

13 



Actions of Electricity. 

This is a condition in the electric machine ; if the 
field winding is examined and current traced, it is 
found there are a number of wires in parallel in the 
form of a coil ; the magnetism generated in each turn 
will flow around the entire coil, because the magnetic 
lines of force around the wire that lies next to it would 
repel the first wire's lines of force if they attempted 
to go back around it ; so the easiest path for the lines 
of force of all the conductors is around the entire coil, 
which, in the small diagram (Fig. 5) will be if the 
coil's end marked A is positive. The current within 
the coil will flow in the same direction as the 




SAUENT POLE FIEU> MAGNET. 
Fig. 5. 



hands of a watch. The lines of force will flow 
from the observer to the north pole, where they leave 
the magnet, and flow through the air or an armature, 
if there were one there, to the south pole of the mag- 
net, where they enter and return again 
field magnet. 

14 



through the 



Actions of Electricity. 



A magnetic field's strength is in proportion to the 
volume of volts and amperes and the number of 
turns of wire in its producing coil. 

If you will examine the armature of the small motor, 
you will find an iron ring around which is wound a 
coil of wire, this coil being tapped and connected to 
commutator bars which serve the purpose of leading 
the current to and from the armature winding by 
allowing the current to flow under each field of the 
magnet in the same direction at all times of a revolu- 
tion ; however, on all economical machines, a greater 
number of coils are tapped to commutator bars, thereby 
making that machine more efficient. 




Fig. G. Fig 7 

If a current is sent through the magnet field coils, 

lines of force will flow from the north pole to the 

armature ring and from the armature ring to the 
south pole. 

If a current is sent through the coils on the arma- 

15 



Actions of Electricity. 

ture ring at that same time, lines of force are set up 
from each turn and repel those of the field, as shown 
in Fig. 7; they cause the field lines to crowd away, as 
two different sets of lines of force cannot occupy the 
same space or flow in the same direction at the same 
time. 

This action in turn causes the flux of lines around 
the conductor to crowd away from the true center to 
their conductor; the torque, or pulling effect, of these 
lines on the conductor to bring it to their true center, 
will cause the armature to move forward. 

By referring back to Fig. 6 and to the motor, and 
applying above condition, we can easily see that, while 
the conductors under the north pole must travel in an 
opposite direction to those under the south pole, the 
current in the armature coils between the armature ring 
and the field's north pole and the armature ring and 
the field's south pole also flows in an opposite direction, 
making a constant pull on the armature in the same 
direction. 

The direction of rotation of a motor armature can 
be ascertained if the direction of flow of current in 
the armature and the direction of flow of magnetism 
in the field is traced. By referring to Fig. 6, the lines 
of force in the field are flowing from the north pole, 
and the current in the armature coils between that pole 
and the armature ring is flowing from us observing it ; 
hence, the field lines of force will crowd those lines 
around the armature conductors to the right and tend 
to push the armature in the direction that the arrow 
points. 

By the above, we can readily see that, to change the 
direction of flow of current in both the armature coils 
and the field coils will not reverse the direction of the 
rotation of the motor, but to change the direction of 
flow of current in either the field or armature and let 

16 



Actions of Electricity. 

the other remain will change the direction of rotation 
of the armature. 

There are various types and connections of direct- 
current machines, shunt or multiple, series and com- 
pound wound fields, and multiple and series wound 
armatures. 



6666660 Q I OO? 
Lamps^ Lir I 




■Multiple 



Figure 8. — compound wound dynamo. 



Fig. 8 shows clearly the connections of a compound 
wound generator. The current produced in the arma- 
ture leaves at A and flows to the lamps through the 
line returning from the lamps flowing through the 
series field winding and back to the armature. The 
shunt field is connected to the positive lead, the current 
flows around the multiple field winding through a 
rheostat, which is only an adjustable resistance and 
connects to the negative lead of the machine. 

It has been shown by the action of the electric cur- 
rent in the motor that magnetism is the means of ob- 
taining power by expending the electric current's en- 

17 



Actions of Electricity. 

efgy, and it has been mentioned before that dynamic 
electricity is obtained from magnetism. 

If a conductor with a closed circuit is moved across 
a space in which there are flowing lines of magnetic 
force at right angles to it, the conductor will tend to 
cut these lines of force, which action will send a 
charge of electricity through the conductor. 




Fig. 9. 



A.M. 



By referring to Fig. 9, the long arrows represent 
a field of lines of force flowing from the north pole 
to the south pole. A wire conductor is cast into this 
field at right angles to the lines of force and is con- 
nected to two commutator bars ; these bars are con- 
nected to two brushes, marked B Positive and B Nega- 
tive, and these brushes are connected to a closed cir- 
cuit through an ampere meter. 

It can readily be seen that, with the wire turned a 
part of a revolution near its shown position, it will 

18 



Actions of Electricity. 



move nearly in the same direction as the field magnet- 
ism is flowing; but if the wire is turned one-fourth of 
a revolution it will be cutting lines of force at the 
fastest possible right-angle rate, and a current of elec- 
tricity will be shown flowing through the ampere meter. 
After the conductor has passed one-half of a -revolution 
it will begin cutting lines of force in the opposite direc- 
tion; therefore, the direction of flow of current in 
the wire will be reversed; but after one-half of a rev- 
olution the commutator segments will also have 
changed brushes and the current will flow in the same 
direction as before through the meter. 

A conductor cutting lines of force will carry off a 
current in only a certain direction; for instance, if a 
wire cutting lines of force under a north pole is moved 
from left to right, the direction of flow in the wire 
will be away from the observer. 

A short rule for finding this condition is given by 
placing the middle and forefinger and thumb of the 
right hand at right angles to each other, and the result 
will be obtained as shown in Fig. 10. 




Fig. 10. 



After studying the principles and actions of the 
motor and generator, we may wonder why a motor 
pulling no load will not continue to increase in speed. 

19 



Actions of Electricity. 

It is the action of a generator within the motor that 
acts as its speed governor ; for instance, if the direction 
of current within a motor is ascertained, and under 
these same connections and rotation of the armature 
if run as a generator, it will tend to generate a cur- 
rent in the opposite direction to that as supplied when 
run as a motor. This is the condition within the 
motor; for, if a current of, say, 220 volts is supplied, 
the motor will increase in speed until it will he running 
fast enough to generate a voltage (nearly 220 volts) 
whose current tends to flow in the opposite direction to 
that of the motors, and this counter current will stop 
or act as a resistance to the supply current ; if a load 
should come on the motor, its speed will drop, which 
action in turn will lower the counter voltage and allow 
more supply current to flow. 

By noting the above, it can be understood that the 
counter current generated within the motor will allow T 
the supply current to flow only in proportion as the 
load is on the motor. 

Within a generator, pushing a current through a cir- 
cuit, it acts as a motor tending to run in the opposite 
direction from that which it is driven, which action is 
due to the current that is generated flowing through 
the armature conductors and in so doing sets up a 
magnetic flux around each conductor as in the case 
of a motor. If this condition is studied, it will be 
found that the generator is driven in an opposite direc- 
tion from that it would run if run as a motor ; from 
this condition, it can be seen that the more current gen- 
erated, the more power will be required to drive the 
machine. 

There are various types of armature shapes and con- 
nections, the main object of all armature windings 
being to get the longest amount of wire under the fields 
with a minimum amount for connections and turns. 

20 



Actions of Electricity. 



The small motor has a ring winding and is multiple 
wound ; for if we can imagine this style armature wind- 
ing under, say, two pole sets (four poles), it would 
be necessary to have four brushes connected to the 
commutator or one under each pole piece to distribute 
and collect the current equally. 

Drum-wound armatures are found by wrapping the 
coils around the entire armature in the same way as 
wrapping string around a ball. 

The style of winding used in most electric machines 
at the present time is a ring lap (multiple) or a wave 
(series) winding, and is generally used on machines 
having more than one set of poles. 

As seen by referring to Fig. 11, the armature is 



Cross Sect/en of S/ot m 
' Coifs ; 




Co// Leads 
7erm/rra/j. 

Com. Bars . 



Actions of Electricity. 



slotted and the conductor coils are laid in the slots in 
groups; a multiple-wound armature coil can be traced 
by starting at commutator bar a (Fig. 11), through slot 
No. 1 under, say, a north pole, then horizontal with 
the ring of the armature and back in a slot under the 
south pole, connecting to a bar next to the one started 
from, and so on around the entire armature. 

By referring to the small motor, we can see that the 
brushes are connected to the commutator segments 
which connect to the armature winding half way be- 
tween the poles, thereby utilizing all the coils under 
each pole. 

A series winding, unlike a multiple winding, does not 
return from its coil to a commutator bar next to where 
it started, but leads ahead as shown in Fig. 12; this 
type of connecting, it will be seen, throws the entire 
winding. in series; therefore it requires only one posi- 




Fig. 12. 



Actions of Electricity. 

tive and one negative brush connected to the bars lead- 
ing to the coil in the slots half way between either set 
of poles. 

By referring to Fig. 13, we will see that the rotation 
of the armature draws the field's lines of force ahead 




Fig. 13. 



or moves the field magnetic flux ahead from the true 
position of the pole pieces ; this actual condition in any 
machine is overcome by shifting the brushes on the 
commutator back or forward until they do not spark, 
which position when found will be the true magnetic 
field. 



ALTERNATING CURRENT 

An alternating current is a quantity of electricity 

which flows in one direction, then reverses and flows in 

the opposite direction, these reversed directions of 

flow occurring at the rate of from 1,000 to 10,000 per 

23 



Actions of Electricity. 




(VI 

Alternator 
Fig. 14. 

minute ; the current which flows back and forth is in 
practice divided as shown in Fig. 15, which is the time 
of the coil to pass the distance of one set of field poles 
making one complete cycle or two alternations. 




Alternation^ \ v i 
- ^ % ; 



Fig. 15. 

24 



Actions of Electricity. 

From this fact, we can figure that the machine in 
Fig. 14 will produce a current of four cycles per revo- 
lution of the armature. 

As previously explained, the current in the armature 
coils is generated and flows in one direction while pass- 
ing under a north pole, and reverses and flows in the 
opposite direction under the south pole; this is the 
actual condition of an alternating-current electric ma- 
chine, the winding of which is shown in Fig. 14, where 
the coils under all the poles are connected in series, the 
ends of which connect to two rings and the current is 
led from the rings by brushes flowing as generated, 
first in one direction when one half of the coils is under 
a north pole and the other half under the south pole, 
and completely reverses and flows in the opposite di- 
rection when the armature revolves the distance of one 
pole, thereby bringing that half of the armature coil 
that was under the north pole now under the south pole. 

The effect of the magnetism in both direct- and alter- 
nating-current machines is about the same, but there 
is some difference in their conditions; an alternating 
current generator must have its field circuit supplied 
with a direct current from a direct current generator 
or some other outside source, so the magnetic lines of 
force in their circuit will flow in the same direction. 

It is practical in most cases to charge the field of an 
alternating current motor or the series field of a gen- 
erator with a rectified alternating current ; a rectified or 
pulsating current is unlike an alternating current in 

25 



Actions of Electricity. 




Fig. 16. 



that each alternation per cycle flows in the same di- 
rection instead of reversing its flow. This condition 
can be obtained by placing on the shaft of the motor 
(or generator for a series field winding only) a com- 
mutator with as many bars as there are field poles on 
the machine, as shown in Fig. 16, where // represents 
the armature coils, B the commutator on the shaft of 
the machine, and S the leads connecting each bar to 
the second bar. From it, these two sets of bars being 
connected in series with the armature coils and with 
two brushes on the commutator the distance of one, 
three, five, etc., bars apart, will be produced in the 

26 



Actions of Electricity. 

series field C a direct pulsating current, the shunt field 
winding F being excited by a direct current generator. 

An alternating-current motor cannot be started by 
its own power and brought to speed like a direct-cur- 
rent motor, for the reason that the current applied to 
the motor reverses continually in the motor's armature 
coils and the forward pull by the first alternation is so 
quick that the armature cannot get started until the 
second alternation would tend to pull it in the opposite 
direction. For this reason, it is necessary, when start- 
ing an alternating-current motor, to bring it to a speed 
by some outside power that it will have the same "fre- 
quency" (number of complete cycles per minute) as its 
supply current, and that its alternations start at the 
same time and in the same direction as that of its supply 
current. It may then be connected with the supply cur- 
rent, as it will be running fast enough to generate a 
counter current which will prevent a rush of current 
through the armature coils. The phase difference be- 
tween any two machines can be found by connecting 
a bank of lights straight in series with the two circuits ; 
if they are in phase, the lamps will not burn, because 
there is no voltage or phase difference between the 
two circuits; if they are entirely out of phase, the 
lamps will burn brilliantly, for the voltage difference 
between the two machines will be double the voltage 
of one machine. 

As an alternating-current motor runs in phase or 
step with its supply current generator, it will be readily 
seen that the motor wall not gain or lose in speed only 
as its generator gains or loses in speed; and if a load 
should come on the motor, it will not drop in speed, 
but its generated counter current will lag behind the 
supply current which allows more supplied current to 
flow ; the above-mentioned lag is small, but in propor- 
tion to the motor's load. If a load should come on the 

27 



Actions of Electricity. 

motor so heavy as to reduce its speed the distance of 
one pole piece on the armature or one alternation, the 
motor will buck the current of its generator and stop, 
as its counter generated alternations will then be in an 
opposite direction to those of its generator. 

Two-phase alternating-current machines are built 
with two separate sets of windings and four collecting 
rings and are in reality two single-phase machines built 
in one. 

Three-phase machines, the most generally used alter- 
nating current generator, shown in Fig. 17, has on its 
armature three separate windings, each winding being 
one-third of the distance on the armature as the space 




covered by one set of field poles ; the three separate 
armature windings are connected together at one end 

28 



Actions of Electricity. 

and the other end of each is connected to a collecting 
ring. If the current in Fig. 17 is traced, we will find 
that three separate single phases are generated or one 
between each of the three collecting rings; by using this 
method of placing the three separate sets of coils at 
equal distances apart on the armature, it will at once 
be seen that the current will be more equally distrib- 
uted around the armature. It will be possible to get 
three separate phases from only three wires, thereby 
favoring the distribution of the current to various dis- 
tances and places. 

TRANSFORMERS 

By referring to Fig. 18, we will see that a trans- 
former consists of an iron core C around which is 







c 










I 






A , 






A 


■P 1 




I Ratio, 




» m 


H i 




■ 3 




) r-l 


> p \ 




to ' 

'< 1 • 




.*s 


o 








► o 


to 








p-i 


to ; 








I rH 


V 





















Fig 18. 



wound a primary coil marked P which is supplied with 
ingle-phase current, a second or secondary coil 
29 



Actions of Electricity. 

marked ^ which generates a current nearly equal in 
quantity to that in the primary coil. 

If an alternating current is sent through the primary 
coil, a magnetic circuit will be produced around the 
iron core, its strength being in proportion to the 
strength of the current and the length of the coil. As 
this magnetic circuit is constantly reversing, it will 
have a volume ranging from zero to a maximum, and 
the coil in the secondary winding cutting all the lines 
of the produced magnetic circuit (acting the same as 
the coils on the armature of a generator except the 
lines of force move and in the generator the coils move) 
will generate a current equal in quantity to that of the 
primary. 

As the number of lines of force generated within 
the core depends upon the length and the voltage of the 
primary coil, so does the generated voltage of the sec- 
ondary depend upon its length and number of turns 
for cutting lines of force to produce a certain voltage. 
By referring to Fig. 18, if the voltage of the primary 
current is 330 volts and 10 amperes of current are 
flowing, the ratio of transformation being 3 to 1, a 
current of 30 amperes at 110 volts pressure will be 
generated in the secondary coil, or a current of the 
same value with a different voltage and amperage as 
that in the primary coil. 

As the current in the primary coil produces a mag- 
netic circuit in the transformer's iron core, the induced 
magnetic lines of force will tend to generate a counter 
current in the coil, whose voltage is nearly as high as 
that supplied, and it is this condition of reaction that 
allows only a very small amount of supply current 
(known in practice as transformer loss) to flow when 
the secondary coil is open. If under this condition 
a load should come on to the secondary coil, it will at 
once begin cutting the lines of force in the core pro- 

30 



Actions of Electricity. 

duced by the current in the primary coil, and a current 
will flow which will tend to set up a magnetic flux in 
the core in an opposite direction from that of the 
counter generated current in the primary, which condi- 
tion will reduce the pressure of the primary coil's coun- 
ter current, thereby allowing more current to flow in 
the primary coil, or a volume in proportion to that used 
in the secondary coil. The transformer may be used 
to step a voltage up by using the coil with the least 
number of turns as the primary coil. 

Let us refer to Fig. 18; if a tap (wire) were con- 
nected to the secondary coil in its middle, the voltage 
produced between this tap and either end of the coil 
will be only one-half the voltage of the whole coil's 
voltage; this condition is practical where it is desired 
to run a power line for a motor of, say, 220 volts 
the voltage of the entire secondary coil and a line be- 
tween the tap and either end of the coil for a lighting 
circuit of 110 volts. 



31 



Actions of Electricity. 



INDUCTION MOTOR 

The principle of an induction motor is much different 
from that of the direct-current machine, and is similar 
to that of a transformer. It is made up of a "stator," 
"rotor," and "rotor supports" or bearings. 

The stator, as shown in Fig. 19, is a field frame with, 
we will say, three single-phase windings equally dis- 
tributed on its inner surface in the same position rel- 
ative to each other as on a three-phase alternater. 




Fig. 19. (a) (b) 




The rotor is simply a magnetic conductor with a 
number of heavy bars of copper across its outer sur- 

32 



Actions of Electricity. 

face, the bars all being connected at their ends by a 
copper ring. 

If a three-phase current is sent through the stator 
windings, the magnetic circuit produced will whirl 
iorward around the inside of the stator with the same 
principle as that if the field frame of a direct-current 
machine rotated ; with this condition in the stator, the 
heavy copper bars on the rotor cutting the whirling 
lines of force will produce in them a heavy current 
which will produce around the copper bars a flux of 
magnetism, which flux will be opposed, and a pulling 
effect upon the rotor caused by the whirling magnetism 
until the rotor's speed reaches that of the whirling 
magnetism, when no lines of magnetism will be cut 
and no current generated in the bars on the rotor. At 
this speed, if a load should come on the motor, its 
speed will lessen enough that the heavy copper bars 
will start cutting more of the whirling field's line of 
force, which action acting the same as the primary coil 
of a transformer will allow more current to flow 
through the stator coils, whose magnetism will also 
increase and cause a greater torque on the rotor, as it 
will cut the increased magnetism thereby regulating 
the speed. 

When a single-phase circuit only is available for the 
induction motor, it is usually built with a split phase, 
or two phase in multiple, one being placed about one- 
fourth its own distance ahead of the other whose resis- 
tance is about one-fourth that of the other, thereby 
causing one phase to lag producing the action of a 
two-phase current. With this arrangement, the motor 
will have a small starting torque, but after attaining 
its phase speed will act practically the same as if its 
stator were supplied with a double or three-phase wind- 
ing. 

33 



Actions of Electricity. 

ROTARY CONVERTER 

To the present time, by using the rotary converter or 
transformer is the most successful method of changing 
alternating current to direct current or direct to alter- 
nating current, and, as is seen in Fig. 20, the rotary 
converter is a simple direct-current machine and a 
simple alternating-current machine all connected to- 




gether from one winding; if a three-phase current is 
led into the machine through its rings and run as a 
motor, a direct current can be taken from the com- 
mutator; if the machine is run as a motor by a direct 
current, an alternating current can be taken from its 
rings. The value of the current in watts is the same 

34 



Actions of Electricity. 

during any transformation through a rotary, but the 
change of voltage in transforming a current either way 
is : single phase, direct current 100 volts, alternating 
current 71 volts; three phase, direct current 100 volts, 
alternating current 61 volts. 



STREET- AXD IXTERURBAN-CAR CONTROL 
The motors of an electric railroad car are in nearly 
all cases supplied from a 600-volt circuit, the motor's 
armature is usually wound with a series 
thereby allowing a wide range of pulling speed. 

By referring to Fig. 21, the most used system of 
current control shows the handle of the controller con- 
nected to the trolley or positive side of the circuit; if 



winding, 




Fig. 21. 

the handle is moved to the first point, a position making 
contact with the resistance marked R, the current will 
flow from the trolley through the handle of the controll- 
er, through the entire resistance, through the motors M, 
and to the ground or negative wire, returning to its 
generator, thereby making its circuit. As will be seen, 

35 



Actions of Electricity. 

with the controller handle on the first point, the motors 
are connected in series; thereby the voltage on each 
machine is only about 300 volts, and the resistance 
marked R and the resistance within both machines, all 
in series, allow only enough amperage to flow through 
the motors to start the car without a sudden jerk. 
After the car has started to move, the controller handle 
can be moved to the second point, and a little later to 
the third point, where the conditions are the same as 
on the first point, except that less resistance is in the 
circuit; the fourth point has no resistance in its cir- 
cuit, and by the time this point is reached the motors are 
running fast enough to generate a counter voltage 
which will act as a resistance and allow only enough 
current to flow through the motors to keep the speed 
of the car normal at half speed. 

The next or fifth point of the controller connects 
the motors so the current flows through all the resis- 
tance and through the motors connected in multiple, 
thereby increasing the voltage of each machine which 
in turn increases its speed. 

The condition of the sixth point is the same as that 
of the fifth, except less resistance is in the circuit ; the 
seventh point connects the motors in multiple across 
the line without any resistance in its circuit, and is the 
full-speed running point of the car. 

There are different makes of current control, some 
having eleven, some thirteen, and some more points on 
the controller; some makers place a shunt across the 
motor field circuit to weaken the field's magnetism on 
the last point, which condition will lessen the generated 
counter voltage of the motor thereby increasing its 
speed. 

Some interurban electric railroads are operated upon 
a 1,200-volt circuit, and in this case the system of 
control is practically the same as shown in Fig. 21 

36 



Actions of Electricity. 

except that all four motors are connected in series on 
the first or low-speed points, and on the last or high- 
speed points they are connected in two pairs, each pair 
being in series, the two pairs in multiple. 

ELECTRO-PLATIXG— ELECTROLYSIS 

Let us drive into the damp earth one copper bar and 
one iron bar and connect a direct current of electricity 
to the exposed ends of the bars so the current will flow 
from the copper bar to the iron bar through the damp 
earth ; this action of the current leaving the copper bar 
will decompose it and make a deposit of copper on the 
iron bar where the current enters it ; this action is called 
electrolysis and is used practically only for electro- 
plating. By referring to Fig 22, a cleansed spoon and 




FlG. 22. r Electro- plating. 



coin are placed in a non-acid, current-carrying solution 
(usually cyanides of silver and potassium) and con- 
nected to the negative side of a battery or low voltage 
generator. The positive current from the generator 
or battery is connected to a plate (gold, silver, copper) 

37 



Actions of Electricity. 

metal which is desired to be plated on the spoon or 
coin and that metal laid in the solution close to the 
spoon and coin ; the current flowing from the metal 
terminal in the solution to the spoon and coin will tend 
to carry particles of the metal and deposit them uni- 
formly in a solid mass on the surface of the spoon and 
coin. The thickness of the plate caused by the above 
operation will depend upon the strength of the current 
and the time allowed to flow. 

STORAGE BATTERY 

Years ago, some scientist discovered that if two metal 
plates were immersed in a solution of acid and a cur- 
rent of electricity sent through the acid from one plate 
to the other, a chemical action of the acid and plates 
would take place. If that current were removed and 
a wire connected to the two plates, a current of elec- 
tricity flowed in an opposite direction, which was pro- 
duced by a further or rather reversed chemical action 
in the acid and plates. 

The extensively used small or large storage battery 
of to-day does not vary in principle from the above. 
The experimenters have found that one of the most 
efficient batteries is made up of a sulphuric-acid solu- 
tion ; the plates are usually a lead grid framework 
and made solid by covering the grid with oxide of lead, 
which is the best material known to produce the re- 
quired chemical action between itself and the acid 
when the battery is being charged or discharged. 

The lead grids or plates are placed side by side in 
the sulphuric-acid solution and are kept from touching 
each other by placing between them glass tubes or per- 
forated hard-rubber plates. There may be as many 
plates as desired in a single cell ; usually the end plate 
and each third, fifth, seventh, etc., plates from it are 

38 



Actions of Electricity. 

|typicai, storage battery. 




Fig. 23, 



connected together, and form the negative, while the 
second, fourth, sixth, etc., plates from the end are 
connected together and are made the positive. 

After a battery is once charged, it will produce a 
current in voltage and volume as great as that con- 
sumed in charging, and acts only as a storage for 
electrical energy by the process of a chemical action 
and reaction; any single cell, regardless of its size, will 
produce only about two volts, but from one to one and 
one-half amperes per square foot of plate surface area. 

AUTOMOBILE ELECTRIC EQUIPMENT 
The electric equipment of an automobile usually 

39 



Actions of Electricity. 

consists of a battery, ignition system, generator, motor, 
lamps, wiring, switches, etc. 

The ignition system's current is of very low amper- 
age and high voltage, and is produced either by a mag- 
neto or current from a battery run through a voltage 
step-up coil or transformer; the voltage of the current 
must be high enough that it will jump through space 
nearly one-fourth of an inch, so when the circuit is 
closed to the spark plug it will jump the gap of the 
plug's contacts, thereby making an arc or a spark and 
exploding the gas. 

The current is led from its source to a distributer 
(which is a mechanical appliance connected with the 
engine shaft) that closes the circuit at the same instant 
during that part of a cycle or revolution that a charge 
of gas is correctly ignited in the cylinder. 

The lower half of Fig. 24 shows the connections for 
an electric lighting and engine-cranking system used 
only on the smaller size engines, as can be seen by 




Fig. 24. IxslSiSlZSi&iJ 




40 



Actions of Electricity. 

noticing the cut. The generator-motor, GM (in this 
system combined in one unit) is connected by wire 
on one side through a relay and starting switch R to 
one side of the battery B and through the lamp control 
switches to the various lamps L ; the other side of the 
generator, battery, lamps, etc., are connected to a 
common ground or the frame of the auto which com- 
pletes the path of the current's circuit. If it is desired 
to light the lamps, their control switch is closed and 
the current will flow from the battery through the 
frame of the auto, through the lamps, returning to 
the battery through the wire and control switches. If 
it is desired to start the motor and crank the engine, 
a lever attached to the relay and starting switch is 
pushed or pulled by the operator that closes the switch 
between the battery and motor, and the current will 
flow from the battery through the motor turning it as 
desired; the starting lever is then released and the 
starting switch opens automatically; this action will 
draw electrical energy from the battery which is re- 
placed by charging the battery in the following manner : 
After the engine is once running at a speed of about 
ten miles per hour on high, the motor-generator be- 
comes a generator whose voltage at this speed is about 
the same or a little higher than the battery voltage, and 
is high enough to produce enough magnetism in the re- 
lay coil to close the starting switch, thereby throwing. the 
battery with the generator ; as the engine speeds the 
generator faster than the above speed, called the "cut 
in" and "cut out" speed, its voltage will tend to rise, 
which action will force more amperes through the bat- 
tery. Let us refer to the upper cut of Fig. 24. As the 
generated ampere load increases, the action of the 
multiple field with one terminal connected to a third 
brush on the commutator midway the main brushes, 
causes the true field magnetism to distort and weaken 

41 



Actions of Electricity. 

in proportion to the ampere increase, until the gener- 
ator will produce seldom more than ten or twelve am- 
peres regardless of how fast the engine is run. 

When the speed of the engine is stopped, or lowered 
to a speed that the generator voltage falls to or a little 
below the battery voltage, the current would tend to 
flow back through the generator, making it a motor, 
which condition will cause the relay to open the start- 
ing switch and separate the battery and generator. 

Fig. 25 shows a complete system of wiring of the 
larger size automobile engine and consists of a storage 
battery, starting motor, and generator as separate units, 
current regulator, switches, lights, wiring, etc. 

Before trying to trace the current of this system, it 
will be noticed that one side of the current has a ground 
flow, or the one side of each apparatus (lights, motor, 
generator, ignition, and battery) is connected to the 
frame of the machine, and the other side of each appa- 
ratus is connected by wire through its control switch 
to the battery, completing the circuit. 

If it is desired to start the engine, the control switch 
is closed by the operator and the current will flow 
from the battery through the frame of the machine to 



42 



Actions of Electricity. 




Tl 



t j j i 




the motor (which is a simple, direct-current motor con- 
nected by a gear or chain to the engine shaft), through 
the control switch, back to the battery, making its cir- 
cuit. 

43 



Actions of Electricity. 

The ignition system and lights are controlled prac- 
tically the same as above, each having in its circuit 
a switch which, when closed, allows the current to 
dow from the battery, through the frame of the ma- 
chine, through the lights, etc., back to the battery. 

The control of the generator is left entirely to the 
regulator which acts automatically to perform its duty ; 
the generator is geared to the engine shaft and is mul- 
tiple field wound. Let us refer to the action of the 
regulator, the normal condition of which is shown that 
the "regulating spring'' holds the "regulator contacts" 
closed, thereby closing the multiple field circuit of the 
generator; the "cut out" and "cut in" contacts which 
connect the generator with the battery, are normally 
open until the speed of the engine is running the auto 
at a speed of about eight to ten miles per hour, at which 
speed the generator will be running fast enough to 
generate a voltage as high or a little higher than the 
normal battery voltage and will be forcing enough cur- 
rent through the multiple field circuit which has in 
series with it a shunt coil, which coil will produce a 
magnetic flux strong enough to pull the "cut in arma- 
ture" toward it, thereby closing the contact points and 
throwing the generator and battery together. 

The condition of the regulator will remain the same 
as above so long as the generator does not vary in 
speed; should the generator lower in speed, its voftage 
will also lower to an amount that no current will flow 
through the series coil and not enough through the 
shunt coil in series with the multiple field winding to 
hold the cut-out armature, and its spring will pull the 
cut-out contacts apart, separating the battery and gen- 
erator. 

Again, after the battery and generator are thrown 
together and the generator increases in speed from its 
"cut in" speed, the current and voltage w r ill tend to 

44 



Actions of Electricity. 

increase also, but as a "series compensating" coil is 
in series with the armature circuit, which when cur- 
rent is flowing in it large enough not to be injurious to 
the battery a magnetic flux will be generated in it that 
will pull the "regulating armature" toward it, thereby 
opening the multiple field circuit; but a part of the 
current will continue to flow through the "regulating 
resistance" which does not permit the magnetic field to 
be destroyed but weakens it, thereby lowering the volt- 
age and amperes of the armature, which action will 
reduce the magnetic pull of the "series compensating" 
coil and let the regulating armature release and close 
the "regulating contacts." This action is continuous 
and the faster the speed of the generator the quicker 
the contact points will open after closing, thereby keep- 
ing the voltage and amperes to a minimum regardless 
of the speed of the generator. 

Later improvements on this system have connected in 
the battery circuit a relay coil which automatically 
opens the battery circuit when the battery voltage is a 
maximum at which point the battery is fully charged, 
thereby saving the battery from being constantly 
charged on long runs. 



45 



Actions of Electricity. 



ELECTRIC ARC LAMPS 

When an electric current flows through space, it 
tends to heat both conductors between which it is flow- 
ing, and is the condition within an arc lamp. By 
referring to Fig. 36, w r e will note two carbon conduc- 
tors that are automatically held separated while a cur- 
rent of usually about fifty volts and six amperes is 
flowing through the lamp and across the space between 



— 




co«-J„ 






the separated carbons. The action of the current leav- 
ing the positive carbon and flowing to the negative 
carbon with the above-mentioned current will cause 
the ends of the carbons to become heated to nearly 
9,000° Fahr., at which heat they will be brilliant white 



46 



Actions of Electricity. 

and produce a light of possibly 1,500 candle power. 
The action of the current flowing across the gap in 
the carbons tends to decompose the positive carbon 
and carry its particles in the same direction as its flow, 
which condition will cause the positive carbon's end to 
form in the shape of a crater and the negative carbon's 
end pointed. 

While no current is flowing in the lamp, the positive 
carbon drops and makes contact with the lower carbon ; 
when a current is started through the lamp, the posi- 
tive carbon is instantly separated from the lower car- 
bon by the action of the series coil's magnetism pulling 
the iron core or solenoid toward it, thereby raising the 
washer clutch which catches the carbon and raises it 
also. The fact that the wider the arc "gap" between 
the two carbons the higher will be the resistance, and as 
the magnetic pull of the shunt coil on the solenoid is 
constant, and in an opposite direction from that of the 
series coil, the solenoid will be held in a balanced posi- 
tion at which the carbon arc gap will be about one- 
fourth of an inch and just enough to allow a current 
of six amperes to flow. Where arc lights are con- 
nected in series, as in street lighting, and the light 
ceases to burn while the current is still flowing (which 
is caused by a carbon sticking or burning out), the 
current is permitted to flow through the lamp by the 
action of a relay that by-passes the current across the 
arc gap. 

ELECTRICAL TROUBLES 

There are various kinds of trouble that occur occa- 
sionally to any electrical apparatus. It has been heard 
said in the practical operation that electrical units seem- 
ingly never show the same effect when in trouble ; 
hence it can at once be seen how important it is to 

47 



. Actions of Electricity. 

know the current's primary actions and principles when 
trying to locate an improper condition within an elec- 
trical apparatus. 

Various kinds of trouble may occur and we will take 
up the two most usual, namely, "short circuits" and 
"open circuits. " A "ground" or short circuit may be 
caused by a punctured insulation on some current- 
carrying lead, which condition will allow the current 
to flow through a conductor, thereby leading it away 
from its proper course of flow through the apparatus. 
This condition will usually require a heavy supply of 
current or power, and can sometimes be located by the 
extra heat produced at the place where shorted by the 
flow of a volume of current ; however, if there is no 
heat produced, a test will be required to find the wrong 
path of the current. 

Open circuits are very common and is a condition 
where a current is stopped from flow by contacts or 
connections being separated (by vibration or other 
cause) ; a lead in the circuit may have become heated 
and melted, thereby separating, or a break in any con- 
ductor where its ends are apart will prohibit the current 
from flowing : in nearly all cases of trouble, if the 
open contact is not where it can be seen, it will be 
necessary to make a test to locate the open in the cir- 
cuit. 

REVIEW QUESTIONS 

The following questions are very simple and can be 
answered if the contents of this book are first familiar- 
ized. The reader is asked to make answers in his 
own language and draw diagrams of his own made- 
up style so far as possible without referring to the 
book, and afterward compare, so an impression will 
be made upon the mind and the subject will be more 
easily remembered. 

48 



Actions of Electricity. 

1. What is electricity? 

2. Name at least two kinds of electricity. 

3. What kind of electricity causes lightning? 

4. How is static electricity produced? 

5. Name two important properties of dynamic 
electricity. 

6. Name four units of measure of an electric 
current. 

7. Write the name of some conductors ; non-con- 
ductors. 

8. How many amperes at ten volts pressure will 
flow through a conductor having a resistance of five 
ohms? 

9. What will be the cost of burning ten forty-watt 
lamps eighty hours at ten cents per kilowatt? 

10. Explain how an incandescent lamp produces 
light from electricity. 

11. What is magnetism? 

12. Why will a compass needle point toward the 
north ? 

13. Explain how a magnetic circuit is produced. 

14. Explain the actions of magnetic lines of force 
in detail by a drawing of a direct-current motor. 

15. Make a drawing showing three motors con- 
nected in series on one line and three motors connected 
in multiple on the same line. If the voltage across the 
terminals of one of the motors in series is 110 volts, 
what will be the voltage across the terminal of one of 
the motors connected in multiple? Why? 

16. Explain fully by a drawing how dynamic elec- 
tricity is produced. 

17. How is the speed of a motor controlled? 

18. Explain why a generator requires increased 
driving power as its output load increases. 

19. Make diagrams showing the different styles 
of armature and field winding. 

49 



Actions of Electricity. 

20. What is an alternating current? a pulsating 
current ? 

21. What is the frequency of an alternating current 
generator having thirty field poles and running 120 
revolutions per minute? 

22. Why will. an alternating current motor not start 
itself ? 

23. What is a transformer? 

24. The primary coil of a transformer has flowing 
in it a current of 1,000 amperes at 500 volts; at what 
voltage and how many amperes w 7 ill flow in the sec- 
ondary coil if the ratio of transformation is 1 to 10? 

25. Explain in full the action of an induction 
motor's magnetism. 

26. Explain how to change an alternating current 
to a direct current. 

27. How is the current controlled within an elec- 
tric street or interurban car? 

28. Explain the method of plating with electricity. 

29. Explain the action of an electric battery. 

30. What is a solenoid ? 

31. Describe the action of an automobile electric 
battery system. 

32. Make a drawing of the control of an automo- 
bile battery system and explain from it the action of 
its control in detail. 

33. What is the temperature of an arc lamp's arc? 

34. Explain the action of an arc lamp from a draw- 
ing. 

35. If a motor would not start when a current is 
applied, what would you do? 



50 



